In a mobile communications network, the access element from the mobile network to another telecommunications network, and vice versa, is a MSC (mobile switching center) through which not only calls and call-related signalling but also non-call related signalling transit.
For example, in the GSM (global system for mobile communications), a BSS (base station subsystem) includes a plurality of base transceiver stations for communicating with mobile stations through the radio interface and a base station controller. The BSS is connected to the MSC which can access registers such as a HLR (home location register) using a SS7 (signalling system No.7) interface and a VLR (visitor location register) being usually included to the MSC. Using several MSC's connected to each other with trunk lines via the SS7 interfaces, it is possible to build a mobile subscriber serving network which has a large coverage area. And the MSC is connected via the SS7 interface to a communications network such as a PSTN (public switched telephone network) or an ISDN (integrated services digital network).
The signalling for mobility managements, which are grouped together in MAP (mobile application part), is a highest layer of the SS7. The MAP protocol uses the services provided by the SS7 protocol TCAP (transaction capabilities application part). For example, when a mobile subscriber roams into a new MSC area, the VLR, i.e., the MAP user, may request service profile information from the HLR using the MAP information carried within TCAP message. The TCAP supports the exchange of non-circuit related data between applications.
The MAP provider system converts a MAP primitive from the MAP user to a TCAP primitive to be transferred to the TCAP and the TCAP primitive from the TCAP to the MAP primitive to be transferred to the MAP user.
The conventional MAP provider system comprises a plurality of a pair of state machines, a DSM (dialogue state machines) and one of a RSM (requesting MAP service state machine) and a PSM (performing MAP service state machine).
The DSM is created per MAP dialogue. When the dialogue is initiated by the MAP user, the created DSM receives a MAP common primitive, e.g., a dialogue start primitive, and a MAP specific primitive, e.g., a handoff primitive, from the MAP user. The DSM converts the MAP common primitive to a TCAP DHA (dialogue handling) primitive, e.g., a unidirectional type primitive.
The RSM that handles a MAP service requested during the dialogue is created by the corresponding DSM for a requested MAP service and converts the MAP specific primitive to a TCAP CHA (component handling) primitive.
On the other hand, when the dialogue is initiated by the TCAP, the created DSM receives a TCAP DHA primitive and a TCAP CHA primitive, e.g, an invoke primitive, from the TCAP. The DSM converts the TCAP DHA primitive to a MAP common primitive.
The PSM which handles a MAP service performed during the dialogue is created by the corresponding DSM for a MAP service to be performed and converts the TCAP CHA primitive to the MAP specific primitive.
In the conventional system, however, it is necessary to provide an amount of memory space for loading processes generated to process the MAP protocol since two processes, one DSM and one of the RSM and the PSM, are created per MAP dialogue. Therefore, it is desirable to provide a MAP provider system capable of reducing required memory space.